BELK-TN-006: Using PetaLinux to Build BELK/BXELK Software Components
Info Box
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History
| Version | Date | Notes |
|---|---|---|
| 1.0.0 | September 2018 | First public release |
| 1.1.0 | November 2018 | Added missing command to generate the DTB file |
Introduction
As explained here, BELK/BXELK structure is not based on the PetaLinux build system (*). Instead, BELK/BXELK make use of a standardized Yocto-based build system to build all the software components—U-Boot, Linux kernel, and root filesystem—that run on the Processing System (PS). This approach is more flexible and more modularized but it requires a little bit more knowledge of embedded Linux systems.
That being said, there are cases in which it can be convenient to build such components with PetaLinux build system, however. This technical note shows how to use the PetaLinux build system to build the Linux kernel released with BELK/BXELK.
The procedure was tested with the following configuration.
| Component | Version |
|---|---|
| PetaLinux | 2017.2 |
| BELK/BXELK | 4.0.0 |
| Host operating system | Ubuntu 14.04.5 LTS |
It is assumed that PetaLinux is already installed on the host machine (for more details, please refer to UG1144 - PetaLinux Tools Documentation: Reference Guide).
(*) Please note that PetaLinux itself works on top of the Yocto build system.
Building the Linux Kernel
First of all, set up the PetaLinux environment:
dvdk@osboxes:~/devel/bora/prj$ source /opt/petalinux/settings.sh PetaLinux environment set to '/opt/petalinux' INFO: Checking free disk space INFO: Checking installed tools INFO: Checking installed development libraries INFO: Checking network and other services
Then, create a project from the zynq template:
dvdk@osboxes:~/devel/bora/prj$ petalinux-create --type project --template zynq --name bora_1 INFO: Create project: bora_1 INFO: New project successfully created in /home/dvdk/devel/bora/prj/bora_1
Import the hardware specification file (.hdf) generated by your Vivado project. This step will open automatically the text-based configuration menu of PetaLinux build system: when it shows up, just exit and save the configuration without changing anything.
dvdk@osboxes:~/devel/bora/prj/bora_1$ petalinux-config --get-hw-description=/home/dvdk/devel/bora/bora-minimal/bora-minimal.sdk/
INFO: Getting hardware description...
INFO: Rename bora_wrapper.hdf to system.hdf
[INFO] generating Kconfig for project
[INFO] menuconfig project
/home/dvdk/devel/bora/prj/bora_1/build/misc/config/Kconfig.syshw:30:warning: defaults for choice values not supported
/home/dvdk/devel/bora/prj/bora_1/build/misc/config/Kconfig:574:warning: config symbol defined without type
configuration written to /home/dvdk/devel/bora/prj/bora_1/project-spec/configs/config
*** End of the configuration.
*** Execute 'make' to start the build or try 'make help'.
[INFO] sourcing bitbake
[INFO] generating plnxtool conf
[INFO] generating meta-plnx-generated layer
~/devel/bora/prj/bora_1/build/misc/plnx-generated ~/devel/bora/prj/bora_1
~/devel/bora/prj/bora_1
[INFO] generating machine configuration
[INFO] generating bbappends for project . This may take time !
~/devel/bora/prj/bora_1/build/misc/plnx-generated ~/devel/bora/prj/bora_1
~/devel/bora/prj/bora_1
[INFO] generating u-boot configuration files
[INFO] generating kernel configuration files
[INFO] generating kconfig for Rootfs
Generate rootfs kconfig
[INFO] oldconfig rootfs
[INFO] generating petalinux-user-image.bb
Your project tree should look like this at this point:
dvdk@osboxes:~/devel/bora/prj/bora_1$ tree -d
.
├── build
│ ├── cache
│ ├── conf
│ ├── misc
│ │ ├── config
│ │ │ ├── data
│ │ │ └── hw-description
│ │ ├── plnx-generated
│ │ └── rootfs_config
│ └── tmp
│ └── cache
│ └── linaro-glibc
│ └── plnx_arm
│ └── x86_64
├── components
│ └── plnx_workspace
└── project-spec
├── configs
├── hw-description
├── meta-plnx-generated
│ ├── conf
│ │ └── machine
│ ├── recipes-bsp
│ │ ├── device-tree
│ │ ├── fsbl
│ │ ├── hdf
│ │ └── u-boot
│ │ └── configs
│ ├── recipes-core
│ │ ├── busybox
│ │ │ └── files
│ │ └── images
│ └── recipes-kernel
│ └── linux
│ └── configs
└── meta-user
├── conf
├── recipes-apps
│ ├── gpio-demo
│ │ └── files
│ └── peekpoke
│ └── files
├── recipes-bsp
│ ├── device-tree
│ │ └── files
│ └── u-boot
│ └── files
└── recipes-core
└── images
49 directories
Clone the Linux kernel sources from DAVE's git repisitory in the :
dvdk@osboxes:~/devel/bora/prj/bora_1/components$mkdir ext_sources dvdk@osboxes:~/devel/bora/prj/bora_1/components$cd ext_sources dvdk@osboxes:~/devel/bora/prj/bora_1/components/ext_sources$git clone git@git.dave.eu/bora/linux-xlnx.git -b bora-4.x.x Cloning into 'linux-xlnx'... ...
Replace the file xilinx_zynq_defconfig with a symbolic link to bora_defconfig:
dvdk@osboxes:~/devel/bora/prj/bora_1/components/ext_sources$ cd linux-xlnx/arch/arm/configs/ dvdk@osboxes:~/devel/bora/prj/bora_1/components/ext_sources/linux-xlnx/arch/arm/configs$ rm xilinx_zynq_defconfig dvdk@osboxes:~/devel/bora/prj/bora_1/components/ext_sources/linux-xlnx/arch/arm/configs$ ln -s bora_defconfig xilinx_zynq_defconfig dvdk@osboxes:~/devel/bora/prj/bora_1/components/ext_sources/linux-xlnx/arch/arm/configs$ ll xilinx_zynq_defconfig lrwxrwxrwx 1 dvdk dvdk 14 set 21 14:30 xilinx_zynq_defconfig -> bora_defconfig
Open the PetaLinux configuration menu and set up the kernel source
dvdk@osboxes:~/devel/bora/prj/bora_1$ petalinux-config
Configure the build system in order to use an external kernel (Linux Components Selection item):
Set the path of the directory containing the BELK/BXELK Linux kernel tree (${TOPDIR}/../components/ext_sources/linux-xlnx):
Configure the build system in order to use a custom directory for device tree include files: enable the Auto Config Settings --> Specify a manual device tree include directory item and set the Manual device tree include directory to ${TOPDIR}/../components/ext_sources/linux-xlnx/arch/arm/boot/dts/include:
Set the Root file system type to NFS in order to generate a uImage that doesn't include any file system:
Exit and save the configuration.
Add the following lines to the file project-spec/meta-user/conf/petalinuxbsp.conf:
LINUX_VERSION_EXTENSION = "-belk-4.0.0" KERNEL_DEVICETREE = "bora.dtb"
Build the kernel:
dvdk@osboxes:~/devel/bora/prj/bora_1$ petalinux-build -v -c kernel [INFO] building kernel [INFO] sourcing bitbake INFO: bitbake virtual/kernel Loading cache: 100% |######################################################################################################################| Time: 0:00:00 Loaded 3234 entries from dependency cache. Parsing recipes: 100% |####################################################################################################################| Time: 0:00:03 Parsing of 2446 .bb files complete (2410 cached, 36 parsed). 3236 targets, 224 skipped, 0 masked, 0 errors. NOTE: Resolving any missing task queue dependencies Initialising tasks: 100% |#################################################################################################################| Time: 0:00:57 Checking sstate mirror object availability: 100% |#########################################################################################| Time: 0:00:21 NOTE: Executing SetScene Tasks NOTE: Executing RunQueue Tasks linux-xlnx-4.9-belk-4.0.0+git999-r0 do_compile: NOTE: linux-xlnx: compiling from external source tree /home/dvdk/devel/bora/prj/bora_1/build/../components/ext_sources/linux-xlnx fsbl-2017.2+gitAUTOINC+122565ec40-r0 do_compile: NOTE: fsbl: compiling from external source tree /opt/petalinux/tools/hsm/data/embeddedsw NOTE: Tasks Summary: Attempted 2410 tasks of which 1869 didn't need to be rerun and all succeeded. INFO: Copying Images from deploy to images INFO: Creating images/linux directory [INFO] successfully built kernel
Create the uImage file:
dvdk@osboxes:~/devel/bora/prj/bora_1$ petalinux-package --image -c kernel --format uImage
SDK environment now set up; additionally you may now run devtool to perform development tasks.
Run devtool --help for further details.
### Shell environment set up for builds. ###
You can now run 'bitbake <target>'
Common targets are:
core-image-minimal
core-image-sato
meta-toolchain
meta-ide-support
You can also run generated qemu images with a command like 'runqemu qemux86'
INFO: Adding user layer: /home/dvdk/devel/bora/prj/bora_1/project-spec/meta-user
INFO: generating uImage
INFO: bitbake -R /home/dvdk/devel/bora/prj/bora_1/build/conf/kerneltype.conf virtual/kernel
Parsing recipes: 100% |####################################################################################################################| Time: 0:03:09
Parsing of 2446 .bb files complete (0 cached, 2446 parsed). 3236 targets, 224 skipped, 0 masked, 0 errors.
NOTE: Resolving any missing task queue dependencies
Initialising tasks: 100% |#################################################################################################################| Time: 0:00:17
Checking sstate mirror object availability: 100% |#########################################################################################| Time: 0:00:12
NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
linux-xlnx-4.9-belk-4.0.0+git999-r0 do_compile: NOTE: linux-xlnx: compiling from external source tree /home/dvdk/devel/bora/prj/bora_1/build/../components/ext_sources/linux-xlnx
NOTE: Tasks Summary: Attempted 2410 tasks of which 2349 didn't need to be rerun and all succeeded.
Compile the device tree:
dvdk@osboxes:~/devel/bora/prj/bora_1$ petalinux-build -v -c device-tree [INFO] building device-tree [INFO] sourcing bitbake INFO: bitbake virtual/dtb Loading cache: 100% |###################################################################################################################################| Time: 0:00:00 Loaded 3233 entries from dependency cache. Parsing recipes: 100% |#################################################################################################################################| Time: 0:01:45 Parsing of 2446 .bb files complete (2413 cached, 33 parsed). 3236 targets, 224 skipped, 0 masked, 0 errors. NOTE: Resolving any missing task queue dependencies Initialising tasks: 100% |##############################################################################################################################| Time: 0:00:02 Checking sstate mirror object availability: 100% |######################################################################################################| Time: 0:00:02 NOTE: Executing SetScene Tasks NOTE: Executing RunQueue Tasks NOTE: Tasks Summary: Attempted 748 tasks of which 748 didn't need to be rerun and all succeeded. INFO: Copying Images from deploy to images [INFO] successfully built device-tree
After the build is completed, the uImage file and the device tree blob (system.dtb) are located in the images/linux directory.
Device tree handling
One of the most appreciated features of PetaLinux is the automatic generation of the Linux Device Tree including the nodes associated with the IPs instantiated in the PL. When used in combination with the Device Tree provided by the BELK/BXELK, this generation process works as depicted in the following image.
In essence, PetaLinux combines the original Bora/BoraX device tree (bora.dts) with another auxiliary device tree generated on the base of hardware description file (.hdf). The resulting DTB (system.dtb) provides all the nodes required by the system to operate properly.
It is worth remembering that the user can add further customizations to the resulting DTB by editing this file <plnx-projroot>/project-spec/meta-user/recipes-bsp/device-tree/files/system-user.dtsi. For more details, please refer to the Xilinx UG1144 PetaLinux Tools Documentation - Reference Guide.
